The UCLA team says the new storage nanocells represent a 10 to 1,000 times power efficiency bump over traditional MRAM designs during the power-intensive write cycle.

Unlike traditional flash memory, which operates using cells that stored values via charge, MRAM cells consist of little nanoscopic "sandwiches", stacks of specially prepared materials. Typically these materials contain a pair of tiny magnetic plates, one permanent, and one adjustable. To write to MRAM, a current induces a shift in polarity, which will remain fixed until the next write.

MRAM is expected to enjoy longevity and speed advantages over NAND or traditional hard-drive-based magnetic storage (which is inherently very slow due to the need for moving parts).

The new MRAM is part of a collection of emerging circuit technologies called "spintronics". Spintronics involves tweaking electron spins to generate novel behavior.
[Image Source: Big Bang Gadget]

MRAM was first developed in the 1990s. A major improvement arrived more recently with the development of spin-transfer torque (STT), a special MRAM technique that uses polarized electrons to trigger a cascade effect and "write" the magnetic value to a nanoscopic in-cell plate.

STT is attractive because unlike with older MRAM designs, it does not require significantly more power to perform a write cycle. However, it still suffered from heat and leakage issues due to the fact that it still required a fair amount of current.

II. Tweaking Spin-Torque

To tackle that challenge, Professor Wang's team modified MRAM cells to use voltage -- a potential difference -- rather than direct current to perform an STT-style write.

Pedram Khalili, a project manager at UCLA-DARPA who participated in the research explains, "The ability to switch nanoscale magnets using voltages is an exciting and fast-growing area of research in magnetism. This work presents new insights into questions such as how to control the switching direction using voltage pulses, how to ensure that devices will work without needing external magnetic fields, and how to integrate them into high-density memory arrays."

"Once developed into a product. MeRAM's advantage over competing technologies will not be limited to its lower power dissipation, but equally importantly, it may allow for extremely dense MRAM. This can open up new application areas where low cost and high capacity are the main constraints."